Various forms of nozzle assemblies, and particularly media-mixing nozzle assemblies adapted to the conditions which prevail in a contact reactor and provided with one or more nozzles, are known in the art.
As an example of the known prior art, reference can be made to such nozzle assemblies as those constructed to produce a finely atomized liquid mist through nozzles incorporated in the nozzle assembly, such nozzle assemblies being designated two-media-assemblies, since such assemblies are used to mix together two media, liquid with gas. In order to atomize the liquid, the gaseous medium, which is accelerated under expansion, is permitted to act upon a liquid surface oriented upstream or downstream of the actual nozzle itself. This liquid surface is given a velocity which deviates substantially from the velocity of the gaseous medium, and is normally much lower than the velocity of the gaseous medium. Nozzle assemblies of this kind can be divided principally into two different categories, depending upon the manner in which they operate. The two categories are distinguished from one another by whether the two media to be mixed meet within the nozzle assembly itself or substantially externally thereof. Consequently, the first category is designated "internal mixing nozzle assemblies" while the second category is designated "external mixing nozzle assemblies."
The present invention relates to an arrangement which can be used to particular advantage in an internal mixing nozzle assembly. An example of such an internal mixing nozzle assembly is described and illustrated in European Patent Application No. 82110320.7, published under No. A0 0 079 081.
The method and apparatus illustrated and described in the Swedish Patent Specification No. 428,096, deriving from the U.S. Patent Application No. 488,472, filed 15 Jul. 1974, now U.S. Pat. No. 4,036,434, also form part of the prior art.
In the technique taught by this specification, a secondary fluid forms around a primary fluid exit aperture a buffer which prevents the fluid from flowing back into contact with a body incorporating the aperture, in a manner to deposit solid substances on the body.
The primary fluid passage is said to be positioned coaxially in relation to a passage for secondary fluid surrounding the primary fluid passage, causing the flow of secondary medium to from a divergent flow immediately downstream of the passage.
The apparatus of this prior art publication is particularly constructed for handling radioactive waste products containing a solution of radioactive substances in slurry form, or solid radioactive substances suspended in a slurry.
The slurry of radioactive waste is introduced into a roasting furnace at a relatively high velocity, with the aid of an injection nozzle located at a distance from the location of a fluid bed.
The known prior art in the present context also includes the apparatus described and illustrated in U.S. Patent Specification No. 2,613,737.
This specification describes an oil-burner nozzle provided with a feed pipe for supplying oil to a chamber in which the oil is mixed with air. The resultant air/oil mixture is fed to a chamber having a plurality of apertures distributed around a hemispherical body.
Secondary air is supplied through a circular slot oriented around the hemispherical body, and consequently when the secondary air exits through the slot the air takes a cylindrical configuration, which is caused immediately to diverge as a result of the air/oil mixture exiting through the apertures in the hemispherical body.